Re: Using libtool via autotools causes linking problem on mingw

[Panicz Maciej Godek]

2013/11/8 Peter Rosin <address@hidden>

On 2013-11-08 12:18, Panicz Maciej Godek wrote:
> 2013/11/8 Peter Rosin <address@hidden <mailto:address@hidden>>

>
>     The SDL library, for some obscure reason, has its own special 

>     take on that and prescribes that you should keep using main()

 

>     even if you are doing a GUI app. I think the SDLmain library 

>     contains the real address@hidden entry point and that entry point 

>     in turn calls the application main function. Or I should perhaps
>     say SDL_main (see that -Dmain=SDL_main define above).

>     Some part of this fragile SDL crap fails. I don't know what.
>
>     Perhaps the SDL_main library was compiled to expect an 

>     ordinary main entry point instead of the GUI address@hidden version?
>
>     Just to be clear, I'm not an SDL user. This is just my 

>     understanding of this.
>     The above description might very well be flawed in some way, but SDL
>     initialization is peculiar.
>
>
> I can later try to add some of the options from the libtool 

> invocation generated by autoconf to my invocation of gcc to see

> which particular option causes the failure and then let you know. 

> I think that your description of the way SDL does things on mingw 

> is sound (and I think that the goal is to ensure portability, as
> unix programmers have no idea what the WinMain is)

Hmmm, I have this hunch that the -nostdlib option that libtool adds to the
g++ invocation beats -mwindows, just like it beats -pthread. But I don't
know that for a fact...

 

I just made the following test: I removed the mediation of libtool

and called g++ directly, with the same flags, i.e.

g++ -D_GNU_SOURCE=1 -Dmain=SDL_main -Ic:/mingw/msys/1.0/include/SDL   -Ic:/mingw/msys/1.0/include/guile/2.0 -I/usr/local/include -Ic:/mingw/msys/1.0/include    -Wall -Werror  -g -O2   -o slayer.exe file.o font.o image.o input.o slayer.o symbols.o video.o   -mwindows -Lc:/mingw/msys/1.0/lib -lmingw32 -lSDLmain -lSDL   -Lc:/mingw/msys/1.0/lib -lguile-2.0 -lgc     -mwindows -Lc:/mingw/msys/1.0/lib -lSDL_image -lmingw32 -lSDLmain -lSDL   -lSDL_ttf 

(the initial part, "/bin/sh ../libtool --tag=CXX   --mode=link", was removed)

and it got linked with no complaints. I then removed both -mwindows flags

from the above invocation, and it did work as well.

So plainly it looks as if there was some problem with libtool on MinGW.

Unfortunately, I'm not a shell scripting master, so I can't say exactly which command libtool uses to link the program and how it is invoked.